Originally Posted by
PAXboy
How many passports does the UK allow you to have? Are the duplicates or they have a new number?
I think the answer is "as many as you can justify (and afford)". There are, or at least used to be, quite a lot of countries that either won't let you in, or at least will make life difficult for you, if you have stamps from certain other countries in your passport.
Not having been in that situation (I had an Israeli stamp once, but that was 3 passports ago), I don't know whether or not they would all have the same number.